Field of Invention
This application relates, in general, to tracking antenna systems, and more particularly to such systems having multiband selectable feeds, and methods for their use.
Description of Related Art
Tracking antenna systems are especially suitable for use aboard ships to track communications satellites while accommodating for roll, pitch, yaw, and turning motions of a ship at sea. For such systems to operate effectively they must point one or more antenna continuously and accurately in the direction toward a respective satellite.
For nearly two decades, Sea Tel, Inc. has manufactured antenna systems of the type described in U.S. Pat. No. 5,419,521 to Matthews. Such antenna systems have a three-axis pedestal and employ a “Level Platform” or “Level Cage” in order to provide an accurate and stable Horizontal reference for directing servo stabilized antenna controls to accurately track communications satellites.
Tracking antenna systems are especially well suited for the reception of satellite television signals, which are typically in the C-band (4-8 GHz) or the Ku-band (12-18 GHz), each band having its relative strengths and weaknesses. For example, C-band signals are susceptible to terrestrial interference, while Ku-band signals are affected by rain and ice crystals. Accordingly, it is desirable for an antenna system to be configured for receiving both C-band and Ku-band signals.
One such system is described in U.S. Patent Application Publication No. 2012/0001816, which describes various systems which include a large primary reflector for C-band satellites and a smaller secondary reflector for Ku-band satellites (see, e.g., '816 publication, FIGS. 15 and 16). Such systems are switchable such that, the primary reflector is aligned with and tracks a C-band satellite in C-band mode, and the secondary reflector is aligned with and tracks a Ku-band satellite in Ku-band.
While such systems are compatible with known and planned satellite television networks, one will appreciate that an antenna system having a single reflector that is configured to receive both C-band and Ku-band signals would be desirable.